Photographic-printing process



' UNITED STATES.

PATENT OFFICE.

JOHN nnweran THORNTON, or WEST narrrsrnan, LONDON, ENGLAND, ASSIGNORZTO zronnownnn OBRIEN, or MANCHESTER, ENGLAND PHOTOGRAIHIC-PRINTING PROCESS.

To all whom it may concern:

Be it known that 1, JOHN EDWARD THORN- TON, a British subject, residing at WVest llampstead, London, England, have invented certain new and useful Improvements in and Relating to Photographic-Printing Processes, of which the following is a specification. i

This invention relates to the production of kinematograph films.

The object of the invention is to prepare a printing belt or belts by which transparent kinematograph films of indefinite length can be produced by mechanical printing of the pictures thereon with applied inks or colours as distinct from printing photographically with sensitive chemical media acted upon by light and as distinct from applying colour to a photographically printed series of pictures.

The original picture film of indefinite length is photographed in the ordinary way and from this the one or more printing belts are prepared by any of the processes known in photo mechanical printing such as relief intaglio, photo aquatint, mezzotint, photogravure, mezzotype, collotype or process analogous to photo lithography.

Photo mechanical printing is defined as :t'callowsel he actual operation of printing requires neither the use of a sensitive surface nor the action of light, nor subsequent development. Instead of such methods printing is eliect-ed by mechanical pressure of the film against a plate '(in the form or" a continuous belt) which has been prepared with a series of images by one of the photo mechanical processes.

The medium used to form the image is therefore a printing or applied ink or colour instead of a sensitive salt. Various kinds of inks or colours can be used according to the particular type of engraved or other printing plate (herein termed printing belt) used.

I prepare a strip or band of copper, steel, brass, aluminium or other metal, or a strip of gelatine, the gelatine being on a supporting base, or a strip of celluloid with a coating of gelatine or other colloid prepared with a sensitive surface in any of the methodswell known for photo mechanical printtone.

Specification of Lette rs Patent. Patgnted F b 2 1922 No Drawing. Original application filed March 21, 1916, $eria1 No. 85,702.

tion filed July 8, 1919. Serial No. 309,425.

Divided and this apiilicamg to receive an impression of the original picture film.

I The prepared strip which is to form the printing belt is perforated or notched along its margins to correspond precisely with the periorations ornotches in the camera f lm and in the transparent kinematograph filmof indefinite length. I Up on theprepared strip I produce a me chanical printing surface, which is herein referred to as a printing belt by photographlcally printing thereon from the orignal picture film by any of the methods here nafter referred to. i I

Instead of printing direct upon the prepared strip the printing from the original picture film may be in 'a similar manner.

upon a transfer to be applied to the prepared strip.

The following represent most of the proc I esses available V Relic processes-The belt is engraved in lellef by the half tone block process, the images being broken up into a series of dots varying in area and shape according to light and shadow. This belt may be a metal one, engraved in the usual way by printing on it by light in bichromatedfish glue, washing out and then etching. ButI prefer to use a belt of celluloid or metal, coated with bichromated fish glue or gelatine printed by light, developed by washing out, andthis image used as the; relief printing plate direct. Or caster moulded reproductions of such printing-belt may be used, such casts being made in celluloid, gelatine, or rubber, mounted upon' a" metal printing belt; Ink is appliedto the raised points by rollers.

Jntaglo pr0cesses. The printing belt is engraved in intaglio by the processes known as photogravure, intaglio or reversed half The images for this process are produced by the same means (merely reversed) as used for preparing the engraved relief belt. Ink or colour is applied to the intaglio image by a plush roller that completely fills it, and the surplus is wiped off the surface of the belt by a scraper, leaving the lines filled to the top Withink, which is afterwards transferred t the film by pressure.

Surface processes.These include all the variations that come under the head of planographic processes, which depend upon the opposition of an image in fatty ink to moisture, such as collotype photo-litho, zincography algraphy and the like.

For collotype the image is formed b the printing belt being covered with a layer of bichromated gelatine printed by light, and w'ashedto remove surplus bichromate. It is then treated with glycerine or various moisture-retaining solutions which are absorbed by the soft gelatine portions of the image not effected by light and repelled by the hardened light-effected portions. When ink or colour is then applied by inking rolls, the ink adheres only to the dry parts and is repelled by the damp portions. It is then transferred to the film by pressure. Such a printing belt can be made of celluloid or metal. For photo-litho, zincography, algraphy and the like processes a grained metal belt is used, though in certain circumstances grained celluloid may be substituted. v

Reversed e0ZZ0 type.For this process the printing belt is prepared similarly to collo type, but comprises a perforated backing or foundation which acts as an ink or colour reservoir, being fed with a watery or spirit.

ink or dye from behind, which therefore passes through the perforations, and through the porous soft gelatine parts of the image, out not through the hardened parts, and is then transferred to the film by pressure.

[J;z (Zr0ty 7e.-For this process the print ing belt of celluloid is made witha bichromated gelatine image in relief, prepared by exposure to light under a negative through the celluloid backing and then developed with hot water from the front thus yielding an image in varyin degrees of relief. This is then soaked in watery ink (a' solution of dye) which is then transferred to the film by pressure maintained for a long enough period to transfer sufficient dye.

By a variation of this hydrotype principle, known as pinatype, the bichroniate image is not developed into relief after exposure, but after washing out the surplus bichromatethe soft parts of the gelatine are dyed up instead of the hardened parts, the dye being next transferred by pressure as before. In still another variation of this principle, known as the Donnistho'rpe process, the hardened parts of the image are dyed.

For single colour or monochrome filmsthe printingfrom the original picturefilm upon the prepared strip to produce the printing belt, is done by any of the methods hereinbefore referred to. I

In preparing printing belts from the original picture film more particularly of the individual elemental colours two or more of such printing belts may be madefrom each, one lightly exposed for the dense parts and the other fully exposed for the lighter tones. By printing from one or other of these printing belts or from both in succession a high degree of tint is reached and desirable or special effects for harmonizing harshness or other defects becomes practicable. Or one of such printing belts may be used for printing say a light shade or tone of blue or a greenish blue, and another for printing a deep blue or a purple blue to give better eflect to the colours in the picture. This mode of operation is regarded as of special importance in relation to originals produced by the two-colour process.

The printing beZts.-The printing belt is made of a strip of indefinite length of metal, celluloid or other material with the pictures etched thereon either in intaglio or relief by well known methods, or any one of the published and current procedures for making a relief or intaglio printing surface. Alternatively bands moulded or formed in rubber, celluloid, gelatine or like may be employed.

A process for forming a printingsurface of actual hardened gelatine is the Leimtype of I'lusnik which is briefly de scribed on pages 330 and 331 of Uassels Ug elopaedia 0 Photography published in 1912, and further a description is given in Husniks British specification No. 37 of 1887.

To obtain the most satisfactory results by the Leimtype process certain improvements and modifications are desirable and these as hereinafter described must be regarded as a part of the present invention. The film base is a flexible band of metal, celluloid or other material grooved or perforated to promote the adhesion of the gelatine with which it is. coated, this coating being on one side or both, and the gelatine having been sensitized and printed and treated in accordance with the Husnik method gives a grained typographic surface, but when an intaglio surface is required the exposure should be under a lined or grained dia-positive. 7

A printingbelt havinga base of celluloid is coat ec with a sensitized resist (as for example bichromated fish glue) similar to that used on metal for ordinary process work. I prlnt upon it from the original picture film and after 'exposure, followed'bv washingout in the usual way, the celluloid is etched by an air blast or a sand blast charged with a solvent of celluloid such for Dr as a preferred method the band may be stamped or cut with numerous small and closely grouped slits or perforations into which the gelatine will penetrate and the slits are best out with a'sharp chisel while the material rests on soft and even metal surface. Further by using a: chisel with several minute gaps in it each slit becomes imperfect; the imperfections affording a desirable unity and strength to the band. This methodhas the advantage or allowing water or glycerine or other liquid to be applied to the gelatine layer from the'back of the band. The picture from the original picture film is printed upon the gelatine layer and treated as in the ordinary collotype process to produce a printing surface.

A printing belt prepared by the collotype process as above described has advantages in relation to the subsequent printing or" the lcinematograph film therefrom in that a stiff water colour or water glycerine colour may be-used' instead of the usual fatty or printers ink as described. in the eleventh article of a series of articles on photo-collotype in the British Journal. of Photography for 187 9; this eleventh article commencing on page are of the volume and the description of the use of stiff water colour inks being on page 411.

The printing belt may be prepared by the reversed collotype process known as hydrotype or pinatype. This method allows of a certain amount of difl'usion of the colour in the. gelatine layer but does not yield extremely sharp images and is therefore better suited for the red image and the yellow image printing over a direct cyanotype or other direct sharp photographic lmage than for all of the three stages of a colour film. For this form of hydrotype a grained or cross hatched or grooved celluloid band is desirable the slight grain resulting therefrom tending to merge into a tone while the graining promotes the adhesion of the gelatine layer. Grooves having vertical sides are specially favourable for giving the gelatine a firm hold on the celluloid.

' it is to be understood that in the subsequent production or printing of the kinen atograph film where there is superimposition of colours or prints some or the printing bands may he mad by one process and some b another process and used in such a way us to give the best results; I

in the preparation of printing belts by any oi these methods in which a screen is employed it is desirable that the screen should be moved slightly-aelatively to the belteithcr laterally or longitudinally or both after each individualpicture is exposed so that the dots or points or lines printed upon the kinematograph film will not "fall in the same place in the successive pictures and so owing to the rapidity oi pro ect1on and the persistence of vision such dots or points will not be visible on the enlarge men; when projected upon a sheet sc en the picture appearing as a full tone nnless picture.

The lciaematogmph film-Thestrip or film upon which-the pictures are '1 to be printed from the p 'inting belts to produce the finished kinematograph film may be of the ordinary celluloid material now employed for kinematograph films or any other transparent film material.

ilr'echam'cal printing of lei-itemcrtogmplz. fiZw1s.In the mechanical printing oi the films from the printing belts herein described any suitable ink or colour may be employed that is adapted to the particular form of printing belt and the surface of the film upon which the print is to be made.

To prevent or minimize adhesion when.

ing surface may be coated or sprayed with animal bile,- or a'solution of the commercial purified ox-gall. The printing may be done by applying the ink to the printing belts by any well known printing method such as by a roller and'in the case of intaglio band removing the excess by a doctor or knife. The printing belts with perforations in which registering pins 'can operate and the film also similarly perforated are drawntogether between rollers or pressing surfaces by which contact or pressure will be applied picture by picture. Sprocket teeth or claws arefitted to draw the two through the machine in correct register.

The printing belts provided by this invention -may be used to produce pictures which are either single tone monochromes. double tone monochromes or heliochromes, and the successive printings may be used either "for the purpose of intensifying parts of the images or for printing them in double tone monochrome or in multi-color heliochrome. I

Vi hat l claim as my invention and desire protect by Letters Patent is:- l. A printing belt of continuous indefinite length for printing a series pictures upon a continuous indefinite length of transparent kinematograph pos ive film provided ipon its margins -with perforations accurately spaced and upon its at face, a series 0i pictures sion longitudinally thereon formed in in succesbroken tone markings and having com plete range of gradations of tone from light to dark (as distinct troin solid patches of colour) the gradations consisting in va-- as in claim 1, bearing a series of photo mechanical cliches having pictures in succes sion longitudinally thereon Which are different on each belt, for the purpose of forming a section of an image or series of images,

the screen owing to their displacement in each succeeding picture and .to the law of persistence of vision, thus giving on. the screen a picture apparently in full tone Without lines, dots, or pattern.

4-. ln apparatus for producing continuous transparent kinematograph positive films of indefinite length, a series of perforated or notched printing belts as in claim 1, each bearing a section of a series, of images in the form of photo mechanical cliches having pictures in succession longitudinally thereon, in which the incidence of the broken tone markings is shifted to a different part of the same image in every belt of the series, in order that when a film is printed therefrom by successive impressions from each belt of the series, the dots or'pattern visible at the first impression from the first belt will'be gradually obliterated by the succeeding impressions from the other .belt, thus producing a series of printed full tone images Without visible broken tone markings.

5. In apparatus for producingcontinuous transparent kinematograph positive films of indefinite length a perforated or notched printing belt or belts, as in claim 1, bearing a series of photo mechanical images arranged in succession longitudinally thereon and having all the gradations of a photograph and produced by any photo mechanical process by Which the original full tone photograph is transformed into a half tone photograph by splitting the image into a number of broken tone markings and capable of yielding a series of prints longitudinally on a continuous stripof film by means of applied ink and pressure.

6. i A continuous printing belt of indefinite length for photo mechanical printing as in claim 1, bearing a series of cliches having pictures arranged in succession longitudi 7. In apparatus for producing continuous transparent kinematograph positive films of indefinite length, a perforated photo mechanical printing belt as in claim 1, bearing a series of clichs having pictures in succession longitudinally thereon that. Will give one part only ofa series of graduated pictures inbrokentone markings, and a second or similar printing belt bearing the other sections of theseries of graduated pictures, so that two impressions from two printing belts are required to produce a series of pictures.

8. In apparatus for producing continuous transparent kinematograph positive films of indefinite length, a perforated photo mechanical printing belt bearing a series of cliches having pictures in succession longitudinally thereon thatwill give one part of a series of pictures, and a second and third printing belt bearing the corresponding image sections to complete theseries by means of three impressions from three sectional printing belts.

9. A continuous printing belt of indefinite length as in claim 1, having its surface grooved or toothed to romote adhesion of the clichs formed on its face and prevent their tearing off during inking and print- 10. A series of perforated 'photo mechanical printing belts having a series of pictures longitudinally thereon for producing continuous indefinite lengths of transparent kinematograph positive films as in claim 1 for printing the. main part of each image by one printing belt and intensifying parts of each image by printing from. another nesses. 7

JOHN EDWARD THORNTON. Witnesses: c

. IOWDEN OBRmN,

W. G. AFNORSWORTHY. 

